The present invention relates to a high-frequency treatment tool for an endoscope.
Generally, in a high-frequency treatment tool that is inserted through an instrument channel of an endoscope and is used for incision of mucous membranes of in vivo tissues inside a body cavity, a partially elongated electrode is equipped at a distal portion of an insulated flexible sheath. The electrode is connected to a conductive operation wire, which can be operated from a proximal side thereof so that the electrode can be protruded outwardly or retracted inwardly from the distal end of the sheath. The high-frequency treatment tool is widely used and examples of such a tool are disclosed in Japanese Patent Provisional Publication No. P2002-113016A and US Patent Application Publication No. US 2004/0210284 A1.
When the high-frequency treatment tool is used for the incision, an electrical current with high-frequency flows at a portion where the electrode contact the mucous membranes, and surface of the in vivo tissues is cauterized, thereby the incision is performed. Once the high-frequency treatment as above is performed, the surface of the electrode is oxidized, and thereafter, the living tissues easily stick to the electrode surface and are charred. In such a state, the conductivity of the high-frequency electrode is significantly deteriorated, therefore the electrode is required to be replaced. When cleaning of such an electrode is attempted by scraping, the electrode may be damaged, therefore the electrode may still need to be replaced.
Conventional electrodes, however, as seen in the above referenced publications, are fixed to the operation wires. Therefore, when the electrodes are replaced, operation wires as well or entire units including the flexible sheaths must be replaced, which is wasteful and uneconomical.